Past examination papers, usually bound by subject and year with worked answers. Ghanaian students say past questions, never “past papers”, and the phrase carries more weight here than the translation suggests.
Revising from them is not a supplementary tactic. For the BECE and the WASSCE it is the main method, on the reasonable theory that an examiner setting the same syllabus every year will keep asking the same things.
It works, and it has a cost. A student who has drilled past questions can reproduce an answer and sometimes cannot do the underlying thing, which is a complaint you will hear from every Ghanaian university lecturer who teaches first years.
Use them against the WAEC syllabus rather than instead of it.